<body>
<div id="editor">
	<p>
		<select>
			<option>Some option</option>
		</select>
	</p>
	<h4 style="font-size:40px;font-family:arial,sans-serif;">Heading</h4>
</div>

<script>
	CKEDITOR.replace( 'editor', {
		extraAllowedContent : 'h4{*}'
	} );
</script>
</body>
